Chapter 24 Flashcards
how will a compass align itself in relation to the magnetic field
it will rotate to line up with the magnetic field
what produces a magnetic field
magnets, current carrying wires, loops, and coils
how do magnetic fields interact with moving charges particles and electric currents?
they exert forces on them
how do like poles interact? what about opposite
like poles repel while opposite poles attract
what happens if you cut a magnet in half
you have two smaller magnetics,each with their own poles
What are magnetic materials? How do they interact with the poles of a magnet
they are materials that are attracted to a magnet, they are attracted to both ends
how do you tell the direction of a magnetic field on a compass
the magnetic field is in the direction that the north pole of a compass needle points
the magnetic field of a magnet points ______ from the north pole and _______ the south pole
away; toward
where do magnetic field lines start? where do they end? do they actually end
they start from north and go to south but they travel through the magnet so they don’t actually end but form a closed loop
when a compass is placed near a current carrying wire, the compass moves. Why?
current carrying wires produce a magnetic field that goes in the direction of the finger curl with the right hand rule
what shape are the magnetic field lines around a wire?
they form a circular shape that decrease with distance
for a looped wire, what type of field lines are seen
it looks like a dipole with circles following through the center of the loop, around the outside and back through the center
for a current in a straight wire going up, what is the direction of the magnetic field?
counterclockwise
for a current in a straight wire pointing down, what is the direction of the magnetic field
clockwise
what type of magnetic field does a solenoid form
a strong, internal uniform field and a weak external field
what does the strength of the magnetic field in a solenoid depend on
it depends on the length of the wire and the number of coils it has
For a particle in a magnetic field, at what velocity does the particle not experience a force
when it is not moving
For a particle in a magnetic field, at what angle does the particle not experience a force
when it is moving parallel to the magnetic field
When does a particular experience a force from the magnetic field
when it moves perpendicularly from the magnetic field, the force exerted on the particle is always perpendicular to the plane containing v and B
what angle provides the greatest force on a moving particle
when it moves 90° from the magnetic field
if you have a negatively charged particle, how does the direction of the force from the magnetic field relate to the right hand rule
it is opposite from what we expect
for a particular moving perpendicular to the uniform magnetic field , what motion does it undergo?
uniform circular motion at a constant speed
what direction does a negative charge orbit when in a uniform magnetic field
it orbits int he opposite direction of the positive charge
if a current carrying wire is parallel to the magnetic field, what is the force exerted on it
it is zero
what happens when two current carrying wires are in a magnetic field
they exert forces on eaachother
if two current carrying wires are in a magnetic field and they have a current in the same direction what is the force between them
it is attractive
if two current carrying wires are in a magnetic field and they have a current in opposite directions what is the force between them
it is repulsive
if two current carrying loops have opposite currents, what is the force between them
it is repulsive
if two current carrying loops have the same currents, what is the force between them
it is attractive
what characteristics does a current loop share with a bar magnet
it has a dipole and a north and south character
if a loop has a magnetic dipole, what does it experience in a magnetic field
no net force but it experiences a net torque
what is the magnetic dipole moment
it is the area x the current of a loop. It affects the torque
what angle does the torque depend on in a loop
it depends on the angle between the magnetic dipole and the magnetic field
it is maximum at 90° (perpendicular) and is zero when parallel with the magnetic field
how will a magnetic dipole act in a uniform magnetic field
it will rotate to line up with it
what is a ferromagnetic material
it is a material that is strongly attracted to magnets that can be magnetized
why does magnetism occur
electrons have an inherent magnetic moment
what electrons give an atom a net magentic moment
unpaired electrons
what type of atoms do ferromagnetic materials have
they have atoms that have net magnetic moments that tend to line up and reinforce eachother to create a magnetic moment
how is a material magnetized
when an external magnetic field is applied, the domains in the material will align and grow at expense of other domains which creates a net magnetic moment that is attracted to the magnet
what are magnetic domains
they are regions of aligned magnetic moments in a ferromagnetic material
